SportLampard remains wary of teams at the bottomTough at the top: Frank Lampard believes the Premier League has become far stronger this seasonChris Hatherall13 April 2012Frank Lampard has warned his Chelsea team-mates the Premier League is becoming more difficult than ever before as they prepare to take on Bolton tomorrow.Lampard has fond memories of the Reebok Stadium - his two goals there in 2005 clinched Chelsea's first League title in 50 years and the Blues have won at Bolton for five seasons in a row.Chelsea go to Lancashire on the back of a home defeat against Arsenal while Bolton are on a high after four victories and 10 goals in their last five matches.Lampard, who has not scored in the last seven games, said: "I think there's as lot of strength in depth now."Some of the teams further down the League have bought well and the teams that came up, Stoke and Hull, up have bought well too."Chelsea captain John Terry believes his team are still well placed but praised Liverpool who lead by a point at the top of the table.Read MoreTransfer news LIVE! Arsenal learn Alvarez price; Chelsea eye wonderkidNeville makes fresh title prediction after Arsenal drop more pointsKeane reveals who he wants as next Man Utd manager amid Carrick verdictSponsoredMake 2026 the year of working smarterHe said: "Liverpool have certainly stepped up a gear."Early on in the season they weren't playing well but still ground out results and that's the sign of a good team. It's more like the Liverpool of old."MORE ABOUTBolton WanderersChelsea F.c.Frank LampardReebok Stadium